Line Card

ADP2121: 600 mA, 6 MHz Synchronous Step-Down DC-to-DC Converter

 2009-07-10

【Basic Info】

【Product Feature】

* Peak efficiency: 92%
* Operating frequency: 6 MHz
* Typical quiescent current in auto mode: 36 μA
* Fixed output voltage: 1.82 V
* Maximum guaranteed load current: 600 mA at VIN ≥ 2.7 V
* Input voltage: 2.3 V to 5.5 V
* Typical shutdown supply current: 0.3 μA
* Automatic power-saving mode
* Compatible with tiny multilayer inductors
* Please see data sheet for additional features

【Application】

* Mobile phones
* Digital cameras
* Digital audio
* Portable equipment
* 1-cell Li+/Li-polymer and 3-cell alkaline/nickel
[Geared for applications powerd by these batteries]

【Overview】

The ADP2121 is a high frequency, low quiescent current, step-down, dc-to-dc converter optimized for portable applications in which board area and battery life are critical constraints. Fixed frequency operation at 6 MHz enables the use of tiny ceramic inductors and capacitors. Additionally the synchronous rectifica-tion improves efficiency and results in fewer external components. At high load currents, the device uses a voltage regulating pulse-width modulation (PWM) mode that maintains a constant frequency with excellent stability and transient response. At light load conditions, the ADP2121 can automatically enter a power saving mode that utilizes pulse frequency modulation (PFM) to reduce the effective switching frequency and ensure the longest battery life in portable applications. During logic controlled shutdown (EN ≤ 0.4 V), the input is disconnected from the output and draws less than 0.3 μA current (typical) from the source.

The ADP2121 has an input voltage range of 2.3 V to 5.5 V allowing the use of a single Li+/Li-polymer cell, 3-cell alkaline or Ni-MH cell, and other standard power sources. The converter is internally compensated to minimize external components, and the 1.82 V fixed output voltage can source up to 600 mA. Other key features include undervoltage lockout (UVLO) to prevent deep-battery discharge and soft start to prevent input current overshoot at startup.